authorgravatar for git@vexu.euVeikka Tuominen <git@vexu.eu> 2023-04-23 13:00:33+03:00
committergravatar for git@vexu.euVeikka Tuominen <git@vexu.eu> 2023-04-23 19:09:14+03:00
logf1e43d1f4fde4f7b6909c660ec210f9b14cacb4d
tree41b36885dbc1b57a82e505f4e3d8c1dae977d6d6
parentc3b30a0fd0b0f4f0bd8966cc8c5fadb028d0517e

Sema: emit cast to null panics for function pointers

Closes #14676

2 files changed, 26 insertions(+), 3 deletions(-)

src/Sema.zig+3-3
...@@ -19626,7 +19626,7 @@ fn zirIntToPtr(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Ai...@@ -19626,7 +19626,7 @@ fn zirIntToPtr(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Ai
19626 }19626 }
1962719627
19628 try sema.requireRuntimeBlock(block, src, operand_src);19628 try sema.requireRuntimeBlock(block, src, operand_src);
19629 if (block.wantSafety() and try sema.typeHasRuntimeBits(elem_ty)) {19629 if (block.wantSafety() and (try sema.typeHasRuntimeBits(elem_ty) or elem_ty.zigTypeTag() == .Fn)) {
19630 if (!ptr_ty.isAllowzeroPtr()) {19630 if (!ptr_ty.isAllowzeroPtr()) {
19631 const is_non_zero = try block.addBinOp(.cmp_neq, operand_coerced, .zero_usize);19631 const is_non_zero = try block.addBinOp(.cmp_neq, operand_coerced, .zero_usize);
19632 try sema.addSafetyCheck(block, is_non_zero, .cast_to_null);19632 try sema.addSafetyCheck(block, is_non_zero, .cast_to_null);
...@@ -19852,7 +19852,7 @@ fn zirPtrCast(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air...@@ -19852,7 +19852,7 @@ fn zirPtrCast(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air
1985219852
19853 try sema.requireRuntimeBlock(block, src, null);19853 try sema.requireRuntimeBlock(block, src, null);
19854 if (block.wantSafety() and operand_ty.ptrAllowsZero() and !dest_ty.ptrAllowsZero() and19854 if (block.wantSafety() and operand_ty.ptrAllowsZero() and !dest_ty.ptrAllowsZero() and
19855 try sema.typeHasRuntimeBits(dest_ty.elemType2()))19855 (try sema.typeHasRuntimeBits(dest_ty.elemType2()) or dest_ty.elemType2().zigTypeTag() == .Fn))
19856 {19856 {
19857 const ptr_int = try block.addUnOp(.ptrtoint, ptr);19857 const ptr_int = try block.addUnOp(.ptrtoint, ptr);
19858 const is_non_zero = try block.addBinOp(.cmp_neq, ptr_int, .zero_usize);19858 const is_non_zero = try block.addBinOp(.cmp_neq, ptr_int, .zero_usize);
...@@ -27718,7 +27718,7 @@ fn coerceCompatiblePtrs(...@@ -27718,7 +27718,7 @@ fn coerceCompatiblePtrs(
27718 try sema.requireRuntimeBlock(block, inst_src, null);27718 try sema.requireRuntimeBlock(block, inst_src, null);
27719 const inst_allows_zero = inst_ty.zigTypeTag() != .Pointer or inst_ty.ptrAllowsZero();27719 const inst_allows_zero = inst_ty.zigTypeTag() != .Pointer or inst_ty.ptrAllowsZero();
27720 if (block.wantSafety() and inst_allows_zero and !dest_ty.ptrAllowsZero() and27720 if (block.wantSafety() and inst_allows_zero and !dest_ty.ptrAllowsZero() and
27721 try sema.typeHasRuntimeBits(dest_ty.elemType2()))27721 (try sema.typeHasRuntimeBits(dest_ty.elemType2()) or dest_ty.elemType2().zigTypeTag() == .Fn))
27722 {27722 {
27723 const actual_ptr = if (inst_ty.isSlice())27723 const actual_ptr = if (inst_ty.isSlice())
27724 try sema.analyzeSlicePtr(block, inst_src, inst, inst_ty)27724 try sema.analyzeSlicePtr(block, inst_src, inst, inst_ty)
test/cases/safety/pointer casting to null function pointer.zig created+23
...@@ -0,0 +1,23 @@
1const std = @import("std");
2
3pub fn panic(message: []const u8, stack_trace: ?*std.builtin.StackTrace, _: ?usize) noreturn {
4 _ = stack_trace;
5 if (std.mem.eql(u8, message, "cast causes pointer to be null")) {
6 std.process.exit(0);
7 }
8 std.process.exit(1);
9}
10
11fn getNullPtr() ?*const anyopaque {
12 return null;
13}
14pub fn main() !void {
15 const null_ptr: ?*const anyopaque = getNullPtr();
16 const required_ptr: *align(1) const fn() void = @ptrCast(*align(1) const fn() void, null_ptr);
17 _ = required_ptr;
18 return error.TestFailed;
19}
20
21// run
22// backend=llvm
23// target=native